Collective term for organic matter that can be used to generate electricity, transformed into fuel or used directly to produce heat. It comes primarily from industrial and urban waste, from energy crops, and from biological products, waste and residues generated by farming, forestry or related industries. It's generally considered a renewable energy source since, unlike fossil fuels, the sources from which it is obtained are produced continuously.

Organic waste from agricultural, livestock, and lumber industry products, dead trees, foliage, etc., and is considered a renewable energy source. Biomass can be used as fuel and is most often burned to create steam that powers steam turbine generators. It is also used to make transportation fuels like ethanol and biodiesel, and chemicals like pyrolysis oil that can be burned like oil to produce energy.

Biomass means "natural material", and refers to biological materials that were alive or created during our lifetimes. When burned, biomass materials release heat – just like wood logs in a campfire. Biomass energy uses natural materials like trees and plants. It can also mean waste products like trash. Examples of biomass include grass clippings, wood chips, animal manure, and non-toxic trash. Biomass exists in landfills, where bacteria break down the waste material, creating methane gas in the process, which can be captured and burned. Energy from biomass is most often captured to generate electricity. Biomass specifically excludes coal and petroleum.